21124210400 has 72 divisors (see below), whose sum is σ = 51662177784. Its totient is φ = 8434496000.

The previous prime is 21124210361. The next prime is 21124210403. The reversal of 21124210400 is 401242112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124210403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 426950 + ... + 473850.

It is an arithmetic number, because the mean of its divisors is an integer number (717530247).

Almost surely, 2^21124210400 is an apocalyptic number.

21124210400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21124210400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25831088892).

21124210400 is an abundant number, since it is smaller than the sum of its proper divisors (30537967384).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21124210400 is a wasteful number, since it uses less digits than its factorization.

21124210400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47484 (or 47471 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21124210400 its reverse (401242112), we get a palindrome (21525452512).

The spelling of 21124210400 in words is "twenty-one billion, one hundred twenty-four million, two hundred ten thousand, four hundred".